CouchZen plays sources you add; it sells no channels or playlists; it ships no catalogue of its own.
A test source for store reviewers: the Blender Foundation's open films, three channels that play them around the clock with a guide and catch-up, and one series. Add it in CouchZen under Connections → Add connection, in either form:
https://review.couchzen.com, any username and password (guide optional: https://review.couchzen.com/xmltv.php)https://review.couchzen.com/playlist.m3u, guide https://review.couchzen.com/xmltv.php